Generally, a compact small-sized camera module is applied to various multimedia fields including notebook type personal computers, camera phones, PDAs (Personal Digital Assistants), Smartphones and toys, and to image input equipment including monitoring cameras and information terminals.
The camera module is manufactured employing an image sensor or a photoelectric conversion device such as a CCD (Charge Coupled Apparatus) type or a CMOS (Complementary Metal Oxide Semiconductor). The camera module is also manufactured with focus adjustment function for adjusting size of an image. At this time, the camera module includes a shutter to allow light of an object to pass through an aperture, and a plurality of lenses.
The shutter is a mechanical device capable of adjusting an amount of light reaching an image sensor through the lenses. FIG. 1 is a schematic view of a shutter of a camera module according to prior art, and FIG. 2 is a schematic view for explaining problems that occur during operation of a shutter on a camera module according to prior art.
Referring to FIGS. 1 and 2, a shutter (30) includes a blocking unit (31) for blocking incidence of light to an image sensor, a fixing unit (33) for preventing an arbitrary motion of the blocking unit (31), and a connection unit (32) for connecting the blocking unit (31) and the fixing unit (33). On the drawings, a bottom surface of the connection unit (32) and the fixing unit (33) is mounted with a magnet (10′) for rotating the blocking unit (31), and a vicinity of the magnet (10′) is formed with a pair of electromagnets (50) for rotating the magnet (10′) in response to changes in polarity.
The fixing unit (33) that takes the shape of a plate is fixed to an anchor (42) to allow at least two points to be fixed, and to prevent the blocking unit (31) from moving arbitrarily. The fixing unit (33) includes a plurality of holes (34) removed of remaining parts except for a basic frame and an elastically deformed unit (34a). The fixing unit (33) is bent with elasticity by the rotation of the magnet (10′), and in a case a power to the electromagnet (50) is cut off, the fixing unit (33) rotates the magnet (10′) counter-clockwise in response to the elasticity to allow the blocking unit (31) to return to an original state.
The magnet (10′) is formed with a fixing pole (20′) that penetrates a center thereof, and is rotated by the power applied to the electromagnet (50) about a center axis of the fixing pole (20′).
The shutter (30) of the camera module thus configured is such that the blocking unit (31) is rotated by rotation of the magnet (10′), where collision occurs with peripheral devices during rotation, and whereby the relevant collision parts and a part contacted by the connection unit (32) and the fixing unit (33) disadvantageously cause destruction due to repeated collision and structural stress.
That is, the magnet (10′) is rotated by the power applied to the electromagnet (50) which is in turn affected by a simple repeated application and release of power and cannot accurately control the rotation of the magnet (10′). As illustrated in FIG. 2, a collision occurs, and if the collision is repeated, the structural stress accumulates to disadvantageously cause destruction of the shutter.